This invention relates to a method for the production of tribenzazepine compounds which are useful as the synthesis material of electric charge transportation agents to be used, e.g., in photosensitive materials for electrophotography use and organic electroluminescence (EL) devices.
In recent years, organic substances are mainly used as the photoconductive material of photosensitive materials to be used in the electrophotographic system. Their examples include a photosensitive material comprised of poly-N-vinylcarbazole and 2,4,7-trinitrofluoren-9-one (U.S. Pat. No. 3,484,237), a material in which poly-N-vinylcarbazole is sensitized with a pyrylium salt based pigment (JP-B-48-25658; the term xe2x80x9cJP-Bxe2x80x9d as used herein means an xe2x80x9cexamined Japanese patent publicationxe2x80x9d), a photosensitive material which contains an organic pigment as the main component (JP-A-47-37543; the term xe2x80x9cJP-Axe2x80x9d as used herein means an xe2x80x9cunexamined published Japanese patent applicationxe2x80x9d), a photosensitive material which contains a euteric complex comprised of a dyestuff and a resin as the main component (JP-A-47-10735), a photosensitive material which contains a hydrazone based compound as the main component (JP-A-57-101844 and JP-A-54-150128), a photosensitive material which contains an aromatic tertiary amine based compound as the main component (JP-B-58-32372) and a photosensitive material which contains a stilbene based compound as the main component (JP-A-58-198043). These photosensitive materials seem to have high practical values because of their excellent characteristics, but when various requirements for photosensitive materials to be used in the electrophotographic system are taken into consideration, it is the actual circumstances that a material which fully satisfies these requirements is not available yet. Accordingly, studies are still being carried out actively on the photosensitive materials for electrophotography use in which organic substances, particularly organic electric charge transportation agents, are used.
VanSlyke and Tang et al. have revealed that, when an aromatic tertiary amine containing phenyl, phenylene or biphenylene group is used as an electric charge transportation agent in the positive hole injection/transportation region of an internally connected organic EL apparatus, stability of the optical output is improved and the operating life is thereby prolonged, as they have disclosed for example in U.S. Pat. Nos. 4,539,507 and 4,720,432 and JP-A-5-234,681. Thereafter, in order to obtain more stable optical output, attempts have been made by many researchers to improve aromatic tertiary amine based electric charge transportation agents to be used in the positive hole injection transportation region, and the results have been reported in a large number of patent applications and scientific papers. Examples of these reports include Japanese Journal of Applied Physics, 27, L269 (1988), JP-A-59-194393, Appl. Phys. Lett., 66,2679 (1995), JP-A-5-234681, JP-A-7-331238, JP-A-8-48656 and WO 95/09147 regarding biphenyl based tertiary amines and Appl. Phys. Lett., 65, 807 (1994) and JP-B-7-110940 regarding star burst tertiary amines. However, since these amines are still insufficient for practical use, such studies are conducted more actively by a large number of researchers.
It has been disclosed recently that a compound having tribenzazepine structure in its molecule is useful as an electric charge transportation agent of electrophotography and organic EL device (JP-A-10-59943, JP-A-10-219241, JP-A-10-316875, JP-A-10-324680 and JP-A-10-330365). However, the tribenzazepine synthesis methods so far known were difficult to be applied to the industrial large scale synthesis because of the use of deoxidation reaction by a special reagent (J. Org. Chem., 56, 3906 (1991)).
In view of the above, it therefore becomes an object of the invention to provide a new method for the synthesis of tribenzazepine compounds which are useful as the synthesis material of electric charge transportation agents to be used, e.g., in photosensitive materials for electrophotography use and organic electric field generation devices.
As a result of intensive studies, the present inventors have found a tribenzazepine structure synthesizing method which does not use a special reagent and accomplished the invention based on this finding.
Accordingly, the invention provides (1) a method for the production of a tribenzazepine compound represented by formula (I), which comprises carrying out the process by way of a dehydration reaction of a compound represented by formula (II): 
wherein Y represents a hydrogen atom or an alkyl, aryl, acyl, alkoxycarbonyl, aryloxycarbonyl, alkanesulfonyl or arenesulfonyl group, each of R1 and R2 represents a hydrogen or halogen atom or an alkyl, aryl, hydroxy, alkoxy, aryloxy, acyl, alkoxycarbonyl, aryloxycarbonyl, formyl, carboxyl, sulfo or amino group, each of R3, R4, R5 and R6 represents a hydrogen atom or an alkyl or aryl group, and each of m and n is an integer of from 1 to 4. 
wherein Y, R1, R2, R3, R4, R5, R6, m and n are as defined in the above, (2) a method for the production of a compound represented by formula (I) described in the above item (1), wherein the compound represented by formula (II) is produced by reducing a compound. represented by formula (III): 
wherein Y, R1, R2, R3, R4, R5, R6, m and n are as defined in the foregoing, and (3) a tribenzazepine compound represented by formula (IV): 
wherein Y1 represents a group having the same meaning of the Y, and each of R7, R8, R9, and R10 represents a hydrogen atom or an alkyl group having 10 or less of carbon atoms, with the proviso that all of R7 to R10 are not hydrogen atoms at the same time and that Y1 does not represent hydrogen atom or an aryl group when R8 is methyl group and each of R7, R9 and R10 is hydrogen atom.
In this connection, according to the invention, it is intended that the respective groups represented by Y, R1, R2, R3, R4, R5 and R6 in the formulae (I) to (III) include not only unsubstituted groups but also those which are further substituted with substituent groups as is evident from the following descriptions.
Other objects and advantages of the invention will be made apparent as the description progresses.
Firstly, Y, Y1, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, m and n in the formulae (I) to (IV) are described.
Each of Y and Y1 represents a hydrogen atom or an alkyl, aryl, acyl, alkoxycarbonyl, aryloxycarbonyl, alkanesulfonyl or arenesulfonyl group, and more detailed examples of the groups excluding hydrogen atom, in the case of unsubstituted groups, are an alkyl group having from 1 to 20 carbon atoms, an aryl group having from 6 to 36 carbon atoms, an acyl group having from 2 to 20carbon atoms, an alkoxycarbonyl group having from 2 to 20 carbon atoms, an aryloxycarbonyl group having from 7 to 40 carbon atoms, an alkanesulfonyl group having from 1 to 20 carbon atoms and an arenesulfonyl group having from 6 to 40 carbon atoms.
Their illustrative examples include an alkyl group such as methyl, ethyl, isopropyl, n-butyl, t-butyl, n-dodecyl or cyclohexyl, an aryl group such as phenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, naphthacenyl, pentacenyl or pentaphenyl, an acyl group such as acetyl, propionyl or benzoyl, an alkoxycarbonyl group such as methoxycarbonyl, ethoxycarbonyl or octyloxycarbonyl, an aryloxycarbonyl group such as phenoxycarbonyl or 2-naphthyloxycarbonyl, an alkanesulfonyl group such as methanesulfonyl or ethanesulfonyl and an arenesulfonyl group such as benzenesulfonyl, p-toluenesulfonyl or 2-naphthalenesulfonyl.
Preferred among them is hydrogen atom, an alkyl, an aryl group, an acyl or alkoxycarbonyl group, and particularly preferred is hydrogen atom, an acyl group or an alkoxycarbonyl group.
Each of R1 and R2 represents a hydrogen or halogen atom, a substituted or unsubstituted alkyl, aryl, alkoxy, aryloxy or acyl group or a formyl, carboxyl, sulfo or amino group, and more detailed examples of the groups excluding hydrogen atom and the formyl, carboxyl, sulfo and amino groups, are a halogen atom such as fluorine, chlorine or bromine and, in the case of unsubstituted groups, an alkyl group having from 1 to 20 carbon atoms, an aryl group having from 6 to 36 carbon atoms, an alkoxy group having from 1 to 20 carbon atoms, an aryloxy group having from 6 to 36 carbon atoms, an acyl group having from 2 to 20 carbon atoms, an alkoxycarbonyl group having from 2 to 20 carbon atoms and an aryloxycarbonyl group having from 7 to 40 carbon atoms.
Their illustrative examples excluding halogen atoms include an alkyl group such as methyl, ethyl, isopropyl, n-butyl, t-butyl, n-dodecyl or cyclohexyl, an aryl group such as phenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, naphthacenyl, pentacenyl or pentaphenyl, an alkoxyl group such as methoxy, ethoxy, isopropoxy, n-hexyloxy, cyclohexyloxy, octyloxy or dodecyloxy, an aryloxy group such as phenoxy, naphthoxy, anthracenoxy or pentacenoxy, an acyl group such as acetyl, propionyl or benzoyl, an alkoxycarbonyl group such as methoxycarbonyl, ethoxycarbonyl or octyloxycarbonyl and an aryloxycarbonyl group such as phenoxycarbonyl or 2-naphthyloxycarbonyl.
When these groups have substituent groups, examples of such substituent groups include a halogen atom and an alkyl, aryl, heterocyclic, cyano, hydroxy, nitro, carboxy, sulfo, amino, alkoxy, aryloxy, acylamino, alkylamino, anilino, ureido, sulfamoylamino, alkylthio, arylthio, alkoxycarbonylamino, sulfonamido, carbamoyl, sulfamoyl, sulfonyl, alkoxycarbonyl, heterocyclic oxy, azo, acyloxy, carbamoyloxy, silyloxy, aryloxycarbonylamino, imido, heterocyclic thio, sulfinyl, phosphonyl, aryloxycarbonyl, acyl, silyl or azolyl group.
Regarding R1 and R2, hydrogen atom, an alkyl group, an aryl group or an alkoxy group is preferable, and hydrogen atom is particularly preferable.
Each of R3 to R6 represents a hydrogen atom or an alkyl or aryl group, illustratively, the same group as defined in R1 and R2. Preferably, each of R3 to R6 is hydrogen atom or an alkyl group. Particularly preferred is hydrogen atom or methyl group.
Each of R7, R8, R9, and R10 represents hydrogen atom or an alkyl group having 10 or less of carbon atoms with the proviso that all of R7 to R10 are not hydrogen atoms at the same time. Preferably R7 to R10 are each hydrogen atom or an unsubstituted alkyl group, and one of them is an unsubstituted alkyl group. Illustrative examples of the unsubstituted alkyl group include an alkyl group such as methyl, ethyl, n-propyl, n-butyl, n-octyl, n-dodecyl, isopropyl, t-butyl, 2-ethylhexyl or cyclohexyl. Preferred is methyl, ethyl or isopropyl.
When R8 is methyl group and each of R7, R9 and R10 is hydrogen atom, Y1 represents a group other than hydrogen atom or an aryl group, but preferably, Y1 is an alkyl, acyl or alkoxycarbonyl group.
Each of m and n is an integer of from 1 to 4, preferably 1.
Next, illustrative examples of the compounds of the invention represented by the formulae (I), (II), (III) and (IV) are shown in Tables 1, 2, 3 and 4, though the invention is not limited thereto.
Next, the production method of the invention is described in the following. A scheme of the production method is shown below. 
In the above formulae, Y, R1, R2, R3, R4, R5, R6, m and n are as defined in the foregoing.)
The compound of formula (III) shown in the scheme can be produced using the method described in J. Org. Chem., 56, 3906 (1991). That is, it can be produced by allowing a 1-O-bromo-5H-dibenz[b,f]azepine compound to react with a furan compound in the presence of a strong base.
In illustratively describing, the reduction method from the formula (III) to the formula (II) of the invention is a reduction reaction which uses hydrogen and a catalyst (generally called xe2x80x9ccatalytic reduction reactionxe2x80x9d) or a reduction method which uses, e. g., a diimide reduction reaction. Examples of the catalyst to be used in the catalytic reduction reaction include a heterogeneous catalyst such as Raney nickel or palladium-carbon and a homogeneous catalyst such as chlorotris(triphenylphosphine)rhodium (I). According to the diimide reduction, examples of the method for generating diimide include a method in which decomposition of an azodicarboxylate is carried out and a method in which elimination reaction from N-arenesulfonylhydrazide or N-acylhydrazine is carried out. Preferred reduction method is a method in which a catalytic reduction reaction is carried out using a heterogeneous catalyst.
Examples of the solvent tribe used in the reduction reaction include an alcohol solvent such as methanol or isopropanol, an ester solvent such as ethyl acetate, an amide solvent such as N,N-dimethylformamide or N,N-dimethylacetamide, an ether solvent such as tetrahydrofuran or dimethoxyethane, a hydrocarbon organic solvent such as hexane or toluene and an organic acid solvent such as acetic acid, which may be used alone or as a mixture. When the substrate is soluble in water, water can also be used as a solvent. Amount of the solvent is from 1 to 20 parts by weight, preferably from 5 to 10 parts by weight, based on 1 part by weight of the substrate.
Reaction temperature for the reduction is from xe2x88x9220 to 100xc2x0 C., preferably from 10 to 60xc2x0 C. The reaction period is from 0.5 to 10 hours, preferably from 1 to 5 hours. In the case of the catalytic reduction method, the pressure of hydrogen is from ordinary pressure to 100 kg/cm2, preferably from 5 to 50 kg/cm2.
In the case of the catalytic reduction method, amount of the catalyst is from 0.001 to 20 mol %, preferably from 0.1 to 10 mol %, based on the substrate. In the case of the diimide reduction method, amount of the diimide to be used is from 1 to 10 equivalents, preferably from 1.2 to 5 equivalents, based on the substrate.
Next, the dehydration reaction from formula (II) to formula (I) is described in detail. The dehydration reaction is generally carried out by heating in the presence an acid catalyst. The acid to be used is sulfuric acid, phosphoric acid, an alkanesulfonic acid, an arenesulfonic acid, a Lewis acid, activated clay or a solid acid, of which an alkanesulfonic acid or an arenesulfonic acid is preferable. Particularly preferred is an arenesulfonic acid, and its illustrative examples include benzenesulfonic acid and p-benzenesulfonic acid. Amount of the catalyst to be used is from 0.1 to 2 equivalents, preferably from 0.2 to 10 equivalent, based on the substrate.
Examples of the reaction solvent to be used include an alcohol solvent such as methanol or isopropanol, an ester solvent such as ethyl acetate, an amide solvent such as N,N-dimethylformamide or N,N-dimethylacetamide, an aliphatic hydrocarbon solvent such as hexane or heptane, an aromatic hydrocarbon solvent such as benzene, toluene or chlorobenzene and an organic acid solvent such as acetic acid, of which an aliphatic hydrocarbon or aromatic hydrocarbon organic solvent is preferable. Particularly preferred is an aromatic hydrocarbon organic solvent. Amount of the organic solvent to be used is from 1 to 20 parts by weight, preferably from 2 to 5 parts by weight, based on 1 part by weight of the substrate.
The reaction temperature is from 50 to 200xc2x0 C., preferably from 60 to 150xc2x0 C. The reaction period is from 1 to 20 hours, preferably from 3 to 6 hours.